Lesson Summary. A force, which is a push or a pull, can come in different sizes, directions, and types. They are the result of interactions between two objects. And while each object exerts a force on the other, there may be other forces involved in the interaction as well.ven objects falling downward through the air experience friction acting upward, this time from the air. This special type of frictional force is called air resistance. It's the friction that acts on an object as it moves through the air.
tarmac. n. 1. (Civil Engineering) a paving material that consists of crushed stone rolled and bound with a mixture of tar and bitumen, esp as formerly used for a road, airport runway, etc. Full name: tarmacadam See also macadam. 2. (Aeronautics) the tarmac a runway at an airport: on the tarmac at Nairobi airport.armac. n. 1. (Civil Engineering) a paving material that consists of crushed stone rolled and bound with a mixture of tar and bitumen, esp as formerly used for a road, airport runway, etc. Full name: tarmacadam See also macadam. 2. (Aeronautics) the tarmac a runway at an airport: on the tarmac at Nairobi airport.
Photo: Pembina Institute. Tar sands (also known as oil sands) are a mixture of mostly sand, clay, water, and a thick, molasses-like substance called bitumen. Bitumen is made of hydrocarbonsâthe same molecules in liquid oilâand is used to produce gasoline and other petroleum products.